Cognomen Houysai (Houysai 
) , all over the world, is a very rare family name. The family name Houysai is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Houysai | Thailand |
Rawiwan, Natsikran, Teeravit, and Rattanaphron